1. Field of the Invention
The present invention relates to a device for liquefying a gas.
2. Prior art of the present invention
A conventional device for liquefying a gas, as shown in FIG. 1, includes a vessel 17 in which an amount of liquid cryogen 18 such as Neon, Argon or Nitrogen is contained. In the liquid cryogen 18, there is immersed an object (not shown) to be cooled. Due to heat generation from the object, liquid cryogen 18 is evaporated and the resulting gas cryogen enters into a chamber 13 via a conduit 15 as shown in dotted-line in FIG. 1. Since an interior portion in the chamber 13 is cooled at or below a temparature by a refrigerator 10 which is driven by a motor 27, as cryogen is condensed back to a liquid and resulting liquid cryogen returns into the vessel 17 via the conduit 15 as shown in solid-line in FIG. 1.
However, the conventional device for liquefying a gas has the following drawbacks. That is to say, since gas cryogen and liquid cryogen flow in opposite directions in common conduit 15, both gas and liquid cryogen are mixed, to some extent, with each other, resulting in that smooth movements thereof are prevented. Furthermore, in the case that capacity for liquefying a gas in the chamber 13 is greater than heat quantity radiated from the object, cryogen to be returned to the vessel 17 as a liquid is frozen into ice.